Cnidaria

Question 1

A term that refers to Cnidaria and the Cnetophora is _________.

Answer 1

radiate

Question 2

Of the most important to the ecology of the oceans, and hence economically important group of the Cnidaria is the

Answer 2

Anthozoa

Question 3

The cnidarian body form that is adapted for floating or free swimming is the

Answer 3

medusa

Question 4

The medusa body form is commonly called a jellyfish and is buoyant because it has a lot of the material called

Answer 4

mesoglea

Question 5

A nematocyst is discharged by high _______ within the living cell.

Answer 5

osmotic pressure

Question 6

A strobila is a structure found in the life cycle of members of the class

Answer 6

Scyphozoa

Question 7

The gastrodermis that lines the inside of the gastrovascular cavity of the members of the phylum Cnidaria is primarily composed of

Answer 7

epithelial cells.

Question 8

The _______ cells are undifferentiated stem cells that can mature into sex cells, nerve cells, and other types of cells.

Answer 8

interstitial

Question 9

The support system of the radiate animals is called a hydrostatic skeleton, which means that it is based on the amount of

Answer 9

water pressure

Question 10

Movement by gliding on the basal disc is characteristic of

Answer 10

polyps

Question 11

In jellyfish, the mouth is at the end of the

Answer 11

manubrium

Question 12

Some hydrozoans form floating colonies with several types of medusae and polyps; an example of this type of design would be

Answer 12

members of the genus Physalia.

Question 13

Scyphomedusae have no velum and sometimes have a scalloped margin. Each notch of the margin will bear sense organs called _______ and lobelike projects called

Answer 13

rhopalia, lappets.

Question 14

In some body forms, there is the combination of a velarium and pedalium at each tentacle. This combination will identify which one of the cnidarian classes?

Answer 14

Cubozoa

Question 15

The subclass of the anthozoans that includes the sea anemones, hard corals, and others is the subclass

Answer 15

Ceriantipatharia

Question 16

Which of the following groups includes the soft and horny corals?

Answer 16

Octocorallia

Question 17

The sexes are separate in some sea anemones, while others have individuals with both types of gonads. This latter type of animal is called

Answer 17

monoecious

Question 18

The members of phylum Ctenophora move about by means of

Answer 18

comb plates.

Question 19

A life cycle that has two different body forms is called

Answer 19

dimorphic

Question 20

Reef building corals are members of the class Anthozoa, which are able to grow much faster than other anthozoans because they have a mutualistic relationship with zooxanthellae.

Answer 20

true

Question 21

In some sea anemones, asexual reproduction occurs when pieces of the base are lost during locomotion and these regenerate into new individuals. The method is called pedal laceration.

Answer 21

true

Question 22

Both cnidarians and ctenophores have two cell layers, with an acellular, jelly-like layer in between.

Answer 22

true

Question 23

In many anemones, the edges of the septa are extended into thread like structures that contain nematocysts and gland cells. These structures are called acontia.

Answer 23

true

Question 24

All ctenophores bear both an ovary and a testis. This condition is called dioecious.

Answer 24

false

Question 25

Both cnidarians and ctenophores exhibit extracellular digestion, tentacles, a gastrovascular cavity, and colloblasts.

Answer 25

false

Question 26

Sea anemones move food into the gastrovascular cavity by ciliary action in the siphonoglyph, which passes food into the acontia.

Answer 26

false

Question 27

Sometimes anthozoans will have a mutualistic relationship with algae to enhance their potential for growth. These algae are called zooxanthellae.

Answer 27

true

Question 28

The lid or covering at one end of a nematocyst is called an operculum, and the triggerlike part is known as the cnidocil.

Answer 28

true

Question 29

The nerve nets of the cnidarians are peculiar in that impulses travel in two directions. This is possible because the neurons have vesicles of neurotransmitters on both sides of the synapses.

Answer 29

true

Question 30

The scyphozoan life cycle is as follows: planula, scyphistoma, strobila, ephyra, medusa, sperm and ova, planula.

Answer 30

true

Question 31

The radiates are the simplest animals to possess true neurons, but the neurons are arranged in a nerve net, and there is no brain.

Answer 31

true

Question 32

In the man o’war, the gastrozooids are the reproductive polyps.

Answer 32

false

Question 33

An animal that is protandrous produces eggs first, then sperm.

Answer 33

false

Question 34

The sea pansy is a member of Class Anthozoa, subclass Ceriantipatharia.

Answer 34

false

Question 35

Of the radiates, the ctenophores are most likely to be bioluminescent.

Answer 35

true

Question 36

Feeding by Hydra is stimulated by the presence of ____.

Answer 36

glutathione

Question 37

The larval stage characteristic of the Cnidaria is the _____.

Answer 37

planula